Formation of PbS materials from lead xanthate precursors

Six lead xanthate adducts Pb(S2COR)(2).L [R = Et, Bu-n, L = bipy, TMEDA (tetramethylethylenediamine), PMDETA (pentamethyldiethylenetriamine)] have been synthesised and the structures of all, save Pb(S2COBun)(2). TMEDA (4) which is an oil, determined. Pb(S2COEt)(2). TMEDA (3) is seven-coordinate at lead through three chelating ligands and one weak intermolecular Pb..S interaction. Both Pb(S2COR)(2). bipy [R = Et (1), Bu-n (2)] are dimers in which one xanthate is terminal and the other mu(2) bridging at each sulphur, generating an eight-coordinate lead when the bipy donor is included. Both Pb(S2COR)(2). PMDETA [R = Et (5), Bu-n (6)] are seven-coordinate at lead by virtue of two bidentate chelating xanthate ligands and a tridentate PMDETA; there are no intermolecular interactions. Trends in the Pb-207 NMR chemical shifts mirror the changes in the intramolecular coordination number across the series. Pb(S2COEt)(2). TMEDA (3) has been used to deposit PbS films on glass, Mo-coated glass and Si by AACVD. Pb(S2COEt)(2) also generated PbS nanocubes when decomposed under an autogenerated pressure.